Ocean surface films determine the enrichment of sea spray aerosol with organic matter, which has implications for cloud droplet concentration, cloud albedo and climate.  However, reducing the complexities of marine chemistry to a level of detail appropriate for inclusion into global models is a challenge.  This presentation will describe a recently-developed treatment of the organic enrichment of ocean bubble films and aerosol, OCEANFILMS, which is suitable for inclusion into Earth System models.  OCEANFILMS partitions the ocean organic matter into a small number of macromolecular classes, which are adsorb to the surfaces of oceanic bubbles and enter sea spray through bubble bursting.  In OCEANFILMS, seasonal and geographic patterns in organic fractions are driven by two major groups of macromolecules: a lipid-like class that is associated with primary production, and a semi-labile class of polysaccharide-like and protein-like molecules that can be transported to oligotrophic regions by ocean currents.  In an initial evaluation, the model agrees reasonably well with observed organic mass fractions of “clean” and “generated” marine aerosol on ships and at coastal measurement sites.  Inclusion of molecular interactions at the air-water interface into the model improves agreement with certain observations of the organic composition of marine aerosol, and is supported by sum frequency generation experiments.

OCEANFILMS: A process model for the organic enrichment of marine sea spray particle

251st National Meeting (2016)

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